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2. Invariance of certain spaces connected with the operator A–λ I;Gol’dman;Dokl. Akad. Nauk SSSR,1964
3. Closed linear operators on Banach spaces;Kaashoek,1964
4. Closed linear operators on Banach spaces;Kaashoek;Proc. Acad. Sci. Amsterdam,1965
5. Perturbation theory for nullity, deficiency and other quantities of linear operators;Kato;J. Analyse Math.,1958